Semiconductor manufacturing processes have become increasingly more complex. From the beginning with the creation of discrete transistors and other semiconductor devices through subsequent medium and large scale integrated devices, the number of transistors or independent elements which can fit on to a semiconductor chip has grown exponentially each year. For example, the first integrated processors comprised on the order of 2300 transistors. A recently announced integrated circuit processor comprises more than 220 million transistors. Other circuits are projected to contain over 1 billion transistors in the foreseeable future.
This continued exponential growth of semiconductor manufacturing processes, while contributing to the greatly decreased costs of individual semiconductor devices and products has also exacerbated many production and testing problems associated with commercial semiconductor manufacturing processes. The substantial increase in the density of electronic circuits in the semiconductor integrated manufacturing processes has resulted in the production of many more less-than-perfect semiconductor die or chips. This increase in the production of less than perfect chips and die has spawned a new market for electronic component sellers who find ways to utilize less-than-perfect chips or die to assemble working components.
The many enhancements and advancements in semiconductor manufacturing and packaging processes have resulted in the creation of a number of price sensitive semiconductor product applications for electronic parts sellers. In particular, these electronic parts sellers develop low cost memory modules or other semiconductor devices through the utilization of cost effective processes, including less-than-perfect semiconductor parts.
One method of building memory modules using partially-defective memory parts may use unpackaged semiconductor memories, or die, for all or part of the memory parts used to build a memory module. Using die instead of packaged parts increases the complexity of the fabrication process, but provides substantial savings by eliminating the cost of packaging parts. The use of unpackaged parts to build memory modules, or other electronics, is called Chip-on-Board, or COB. In recent years, improvements in semiconductor memory technology and manufacturing have led to the creation of new memory products and patching techniques implemented using a Chip-on-Board process.
While the process used to assemble Chip-on-Board modules, referring to the process disclosed in U.S. Pat. No. 6,119,049, is effective, modem adhesives provide new methods of mounting unpackaged parts. In particular, an improvement in the yield of Chip-on-Board memory modules can be attained by using one or more selectively settable liquids. A standard burn-in process used to test electronic memory modules (including Chip-on-Board modules) under high heat and high voltage stress may frequently cause a number of failed and broken chips, due mostly to a difference in the thermal expansion coefficients of the chips and the circuit board base.
In summary, there is an ongoing need in the art for means and methods of producing low cost semiconductor devices, particularly memory modules. Related to this is an ongoing need to make use of semiconductor devices that are partially-defective so that such device are not completely wasted. The use of unpackaged parts, including new mounting techniques, is desirable to provide important cost saving practices.